This invention relates to an apparatus and a method of cooling a first air stream, hereinafter also referred to as the stream of air to be conditioned, by means of another air stream, hereinafter also referred to as the auxiliary air stream, in a regenerative heat exchanger having two groups of channels or passageways separated from one another through the walls of which heat exchange between the two air streams is effected.
One main object of the invention is to provide a high cooling effect in the heat exchanger so that conditioning of the air for a space to desired temperature level can be effected solely or at least to a substantial part by means of the regenerative heat exchanger. This is especially important for operation in such climate where warm atmospheric air has low relative moisture content. According to the invention, the walls of the channels or passageways for the auxiliary air stream are kept wetted by intermittent application of an excess amount of water for a short period of time with water which is caused to evaporate by means of this air stream, while the stream of air to be conditioned passes through the intermediate channels or passageways with substantially unchanged moisture content.
The cooling effect is increased further by using as auxiliary air stream wholly or partly an air stream which earlier has passed channels or passageways provided with wetted walls of the heat exchanger or an auxiliary heat exchanger. The invention also comprises an apparatus particularly suited for carrying out the method.